So I ordered from GM Gauge repair, their 5mm WHITE LED cubes and replaced them tonight. I can't say that I am pleased by any stretch of the imagination.
This picture I took, makes it look amazing. Trust me it's not and I can't get the phone to adjust to take it as the human eye sees it. I WISH that it were this bright (they're almost the same brightness as the stock bulbs), the needles this radiant, and not as blue as it turned out.
I may investigate gague face overlays without the blue pigmentation on the backside as their simply isn't a ton of cube LED options;